Apparatus for the control of highway crossing signals



Sept. 5, 1939.

c. w. BELL APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed De o. 51, 1937 02 /H a 21 1% B If g L 5 Q 1) 21: J I? v EH5 2 5. U I

/H M 22, 0 J- I i l I 5 2 22a N I HIS ATTORNEY Patented Sept. 5, 1939 UNITED STATES PATENT OFFICE APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Application December 31, 1937, Serial No. 182,827

11 Claims.

My invention relates to apparatus for the control of highway crossing signals, and has for an object the provision of novel and improved apparatus controlled by a train approaching the highway crossing for governing the operation of a highway crossing signal capable of displaying three distinctive indications. Other objects and advantages of my invention will appear as the specification progresses.

I shall describe two forms of apparatus ernbodying my invention, and shall then point out the novel features thereof in claims.

For a better understanding of my invention, reference may be had to the accompanying drawing, of which Figs. 1 and 2 are diagrammatic views showing two different forms of apparatus and circuits each embodying my invention.

Similar reference characters refer to similar parts in each of the two views.

Referring to Fig. 1, the reference characters I and la designate the track rails of one track and 2| and 2Ia designate the track rails of the other track, of a stretch of double-track railway which is intersected at grade by a highway H. Traffic along each track normally moves in the direction indicated by the associated arrow. Highway crossing signals S and SI are located at the intersection, and preferably face in opposite directions so as to plainly exhibit their indications to highway users approaching the intersection from either direction. The lamps of signal SI are connected in multiple with the respective lamps of signal S, but the circuits for the lamps of signal SI are omitted from the drawing for the sake of clearness. As shown in the drawing, the signals S and SI preferably consist of green lamps G, yellow lamps Y, and red lamps R. The green lamps G are illuminated when no train is approaching the intersection within the limits of the stretch of railway under consideration to display a clear crossing signal to highway users. The yellow lamps Y are illuminated when a train is approaching the intersection to caution highway users that a train is approaching and that a danger or stop signal is about to be displayed. The red lamps R are illuminated when the train has reached a predetermined distance from the intersection to indicate stop to the highway users. It follows that the three indications of signal S correspond to the green, yellow and red traffic signals usually encountered at street or highway intersections. It will be understood that my invention is not restricted to this one form of highway signal, but other types winch are capable of displaying three distinctive indications may be used if desired.

The track rails I and Ia are divided by means of insulated joints 2 to form a track section DE, extending from the highway in the direction of approaching trafiic. A suitable source of current such as track battery 3 is connected across the rails of section DE at the end. farthest away from the highway H, and a neutral track relay TRI is connected across the rails of this section nearest the highway H. Similarly, track rails 2! and 2Ia are divided by insulated joints 2 to form a track section JK, extending from the highway in the direction of approaching traffic, and track battery 3 is connected across one end and relay TRZ across the other end of the rails of section JK. Located at a predetermined point within track section DE is a track instrument or track rail contactor CI, which is attached tothe rails of section DE in any suitable manner so as to be actuated by the train independently of the electrical contact between the wheels of the train and the rails of the section. Similarly a track instrument C2 is located within track section JK and is suitably attached to the rails of section JK. No particular type of track instrument is required, but any of the well-known mechanical, vibration, mercury, or similar types may be used, as for instance that type covered by United States Letters Patent No. 1,834,077, issued to A. J. Sorensen on December 1, 1931, wherein the resistance is normally low but is increased due to the vibration caused by a passing train; or that type covered by United States Letters Patent No. 2,076,928, issued to H. G. Witmer, on April 13, 1937, wherein'a normally closed contact is opened due to the passage of a train.

The length of track section DE is determined by the total length of track that a train will traverse during the period while the caution and stop indications are being displayed by signals S and S1. This distance is dependent upon the maximum speed of trains. using the railway and the minimum period desired for the operation of the caution and stop indications. Assuming, for example, a maximum train speed of 90 miles per hour (132 feet per minute) and a minimum caution period of 10 seconds during which the train will travel 1320 feet, and a minimum stop period of seconds during which the train will travel 2640 feet, or a total operating period for the caution and stop indications of seconds, then a train will travel 3960 feet in that period, and under those conditions track section DE will be .3960 feet in length. Track instrument CI, as

' indication.

will be shown later, controls the stop indication for each signal S and S1, and thus track instrument CI will be located 2640 feet from the highway H. It is understood that these figures are merely illustrative, and that any combination of maximum speed of train and minimum period of display may be used without departing from the scope of my invention. Where in this specification mention is made of other track instruments in other track sections, the location of such track instruments and the lengths of the track sections may be determined as given above.

In addition to the track circuits and track instruments mentioned above, the signal control apparatus consists of a neutral stick relay NR.- A stick circuit for relay NR is provided with current from a suitable source such as a battery, not shown, and which circuit passes from terminal B of the current source, through track instruments C2 and CI in series, front contact 4 and winding 5 of relay NR to the other terminal of the source, designated as C. A pick-up circuit for relay NR is provided with currentfrom terminal B of the current source through front contact 6 of relay TRI, front contact I of relay TR2, and winding 5 of relay NR to terminal 0.

When no train is approaching the highway within the limits of tracksections D-E. and J-K, current from each track battery 3 serves to energize the associated "track relay TRI or TRZ. A circuit is then completed from terminal Bthrough front contact. ID of relay TRI, front contact. II of relay TR2, green lamp G of signal S to .terminal C, so that the green lamp G is lighted and signal S displays its clear indication. When a train moving toward the right approaches the highway and enters track section D-E, the track circuit is shunted through the wheels and axles of the train, relay TRI is deenergized, the circuit for green lamp Gis broken'at front contact II) of relay TRI, and a circuit is then completed from terminal B through back contact 8 of relay TRI, front contact 9 of relay NR, and yellow lamp Y of signal S toterminal C, so that the lamp Y is lighted and signal S displays its caution The pick-up circuit for relay NR is opened at front contact 6 of relay TRI, but'relay NR is retained energized by the previously traced stick circuit. Whenthe train reaches track instrument C |,.the instrument is operated-to deenergize relay NR, thus opening the circuit for yellow lamp Y at front contact 9 of relay NR, and completing a circuit for red lampR from terminal B through back contact 8 of relay TRI, back contact I2 of relay NR, lamp R to terminalC, so that red lamp R is lighted and signal s'displays its stop indication. Y I

When the train has vacated section D-E,- track relay TRI is reenergized, andfront contact II] of track relay TRI closes to complete thecircuit for green lamp G so that signal S again displays its clear indication} back contact 8 of relay TRI opens, opening the circuit for red lamp R-at that point; and front contact 6 of relay TRI closes, completing the pick-up circuit for'relay NR, reenergizing relay NR. 5

A train approaching the highway'on the other track, in the direction of normal traffic through section J-K, will produce asiinilar'operation of signals S and SI by means of the track relay TRZ andtrack instrument C2.- I

In the form of invention disclosed in Fig. 2, 22' and 22a designate the rails of a single track railway over which trafiic normally moves in nearest the highway H. The other magnet 20 of "relay IR is connected across one end, and battery 3 is connected across the other end, of the rails of track section N-O. The remainder of the signal control apparatus is similar to that described in Fig. 1 and includes track instruments CI and C2 located one in each section.

The interlocking relay IR may be of any of the well-known types provided with flagman contacts, and is here shown provided with two front flagman contacts I3 and I 4 and a back contact I5 controlled by magnet I6, and with two front flagmancontacts I1 and I8 and a back contact I9, controlledby magnet 20. If magnet I6 becomes deenergized before magnet 20 becomes deenergized, front contacts I3 and I4 will open and back contact I5 will close. If magnet 20 is then deenergized before magnet I6 becomes reenergized, back contact I9 does not close, and front contacts I1 and I8 remain closed, so that when magnet I6 becomes reenergized closing contacts I3 -and I4, the circuits controlled over contacts I! and I8 are completed. The operation of the relay is similar for corresponding control of windings I6.and,20, in the reverse, order.

When noqtrain is approaching the highway withinthe limits of track sections -M-N and N-O, the front contacts I3 and II of the interlocking relay IR close .a circuit from terminal B to lamp G of signals'gso .that signal S displays its clear indication. Signal S, however, is caused to display its caution indication whenever an eastbound train approaches the highway and first enters section MN, since magnet It then becomes deenergized so that its front contact I3 is opened to'thereby open the circuit forlamp G, and its backcontact I5 is closed to complete .an obvious circuit for lampY. Frontcontact Moi magnet I6 alsoopens when that magnet becomes deenergized, to therebyopen the pick-up circui for relay NR. j

The actuation of track instrument CI when the eastbound train reaches its location within section MN results in the release of relay NR. so that front contact-9 of relay NR opens toopen the circuit for lamp Y, and backcontact I2 ,of relay NR closes to complete an obvious circuit for lamp R, of signal S, with the result that signal S displays its stop indication.

. The entrance of the eastbound train on section N--O results in thedeenergization of magnet 26, but as was pointed out heretofore, this action of magnet 20 does not affect the opening or closing respectively of the front and back contacts controlledthereby, since the deenergized condition of magnet Ili whenmagnet 20 becomes deene rgized prevents the latter winding from operating itscontacts. It is readily apparent that since the contacts of magnet 20 are retained in their original positions, the reenergization of magnet I6 when the eastbound train vacates section MN resultsin'the opening of the circuit-for lamp R and-the closing'of the circuit for lamp-G, so that signal S again displays its'clear indication. 'It is furtherapparent that with magnet I6 energized, the pick-upcircuit for relay NR is completed at front contacts I4 and I8 of relay IR, so that relay NR is held energized over its pick-up circuit during the interval that track instrument C2 located within section NO is actuated by the train. It follows that the actuation of the track instrument located within the track section on the receding side of the intersection does not affect the operation of the highway crossing signals. Then, when the train vacates section N-O and Winding 20 becomes reenergized, it can be seen that the apparatus is restored to its normal condition as illustrated in Fig. 2.

The operation of the apparatus of Fig. 2 for a westbound train is substantially similar to the operation just described for an eastbound train, as will readily become apparent from an inspection of Fig. 2, and further detailed explanation is deemed unnecessary.

One advantage of apparatus embodying my invention is the provision of means for controlling a three indication highway crossing signal without the necessity for more than one track circuit on the approach side of the crossing or the necessity for time element devices.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track intersected by a highway and provided with a single insulated track section extending from said intersection in the direction of approaching traffic, a highway crossing signal capable of displaying three indications and located adjacent to the intersection, a track instrument located within said insulated track section and adapted to be actuated by the mechanical connection of a train with the rails of said section, means effective when no train is approaching the highway for causing the signal to display a first one of said indications, means controlled by a train entering said insulated track section for causing the signal to display a second one of said indications, and means controlled by said train and effective when said train reaches and mechanically operates said track instrument for causing the signal to display a third one of said indications.

2. In combination, a stretch of railway track intersected by a highway and provided with a single insulated track section extending from said intersection in the direction of approaching traffic, a highway crossing signal device capable of displaying a clear indication and a caution indication as well as a stop indication and said signal being located adjacent to the intersection, a mechanically operable track instrument located Within said track section, means effective when no train is approaching the intersection for causing the signal to display said clear indication, means controlled by a train entering the track section for causing the signal to display said caution indication, and means controlled by a train reaching and mechanically operating said track instrument for causing the signal to display said stop" indication.

3. In combination, a stretch of railway track over which traific moves in both directions and intersected by a highway, said stretch being divided into two insulated track sections extending in opposite directions from said highway, a highway crossing signal capable of displaying three indications and located adjacent to the intersection, mechanically operable track instruments located one on each side of said intersection at selected points within said track sections, means effective when both track sections are unoccupied for causing the signal to display a first one of said indications, means effective when either of the track sections is entered by a train approaching the intersection for causing said signal to display a second one of said indications, and means controlled by a train reaching and operating that track instrument within that track section entered for causing the signal to display a third one of said indications.

4. In combination, a stretch of railway track intersected by a highway and provided with a track section extending from said intersection in the direction of approaching trafiic, a highway crossing signal capable of displaying three indications and located adjacent to the intersection, a track circuit for the track section including a track relay, a track instrument attached to a rail at a selected point within the track section, a neutral stick relay, a pick-up circuit for the neutral stick relay including a front contact of the track relay, a stick circuit for the neutral stick relay including said track instrument, means including a front contact of the track relay for causing the signal to display a first one of said indications, means including a back contact of the track relay and a front contact of the neutral stick relay for causing the signal to display a second one of said indications, and means 1ncluding a back contact of the track relay and a back contact of the neutral stick relay for causing the signal to display athird one of said indications.

5. In combination, a stretch of railway track over which traffic moves in both directions and intersected by a highway, said stretch being divided into two track sections extending in opposite directions from the highway, a highway crossing signal located adjacent to said intersection capable of displaying three indications, an interlocking relay, a track circuit for each track section including a magnet of the interlocking relay, track instruments, one located at a selected point within each track section, a neutral stick relay, a pick-up circuit for the neutral stick relay including a front contact of each magnet of the interlocking relay in series, a stick circuit for the neutral stick relay including said track instruments in series, means including a front contact of each magnet of the interlocking relay for causing the signal to display the first one of the said indications, means including back contacts of each magnet of the interlocking relay in multiple and a front contact of the neutral stick relay for causing the signal to display the second one of the said indications, and means including a back contact of each magnet of the interlocking relay in multiple and a back contact of the neutral stick relay for causing the signal to display a third one of said indications.

6. In combination, a stretch of railway track intersected by a highway and provided with a track section extending from said intersection in the direction of approaching traffic, a highway crossing signal capable of displaying three indications and located adjacent to the intersection, a

section for causing the signal to display a second one of said indications, means controlled by the train approaching the highway upon reaching said track instrument for causing the signal to display a third one of said indications, and directional means controlled by the approach of the train to the highway for causing the signal to display said first one of said indications when the train recedes from the highway through said track section.

'7. In combination, a stretch of railway track intersected by a highway and provided with a track section extending from said intersection in the direction of approaching traflic, a highway crossing signal capable of displaying three indications and located adjacent to the intersection, a track circuit for the track section including a track relay, a track instrument attached to a rail at .a selected point within the track section, a stick relay, a pick-up circuit for the stick relay including a front contact of the track relay, a stick circuit for the stick relay including said track instrument, means including a front contact of the track relay for causing the signal to display a first one of said indications, means including a back contact of the track relay and a front contact of the neutral stick relay to cause the signal to display a second one of said indications, means including a back contact of the track relay and a back contact of the neutral stick relay for causing the signal to display a third one of said indications, and directional means controlled by a train when moving in the direction to recede from the highway through said track section to render said track circuit and said track instrument ineffective to control the signal.

8. In combination, a stretch of railway track intersected by a highway and provided with a track section extending from the intersection in e the direction of approaching traflic, a highway crossing signal capable of displaying three indications located at the intersection, a track circuit for said track sectign including a track relay, a track instrument located at a selected point within said track section, a neutral relay governed by said track instrument, means governed by said track relay for controlling said signal to display a first one of said indications, means governed jointly by said track relay and said neutral relay for controlling said signal to display a second one of said indications, and means governed jointly by said track relay and said neutral relay when controlled by a train actuating said track instrument for controlling said signal to display a third one of said indications.

9. In combination, a stretch of railway track intersected by a highway and provided with a track section extending from the intersection in the direction of approaching traflic, a highway crossing signal capable of displaying three indications located at the intersection, a track circuit for said track section including a track relay, a track instrument located at a selected point within said track section, a neutral relay governed by said track instrument, means including a front contact of said track relay for controlling said signal to display a first one of said indications, means including a back contact of said track relay and a front contact of said neutral relay for controlling said signal to display a second one of said indications, and means includ ing a back contact of said track relay and a back contact of said neutral relay for controlling said signal to display a third one of said indications.

10. In combination, a stretch of railway track over which trafiic moves in both directions and intersected by a highway, said stretch being divided into two track sections extending in opposite directions from the intersection, a highway crossing signal capable of displaying three indications located at the intersection, a track instrument for each track section located at a selected point within its track section, means effective when both track sections are unoccupied by a train approaching the intersection for controlling the signal to display a first one of said indications, means efiective when either one of the track sections is entered by a train approaching the intersection for controlling the signal to display a second one of said indications, means controlled by a train reaching that track instrument located within that track section entered for controlling the signal to display a third one of said indications, and directional means governed by the approach of the train to the intersection for controlling the signal to display said first one of said indications when the train recedes from the intersection through the other one of said track sections.

11. In combination, a stretch of railway track intersected by a highway and provided with an insulated section of track extending from the intersection in the direction of approaching traffic, a highway crossing signal capable of displaying three indications and located at such intersection, a track circuit including a track relay for said insulated section of track, a track instrument located at a selected. point within said insulated section of track, circuit means governed by said track relay for controlling said signal to display a first one of said indications, and other circuit means governed jointly by said track relay and said track instrument for controlling said signal to display a second or a third one of said indications, said other circuit means being effective to cause said signal to display its second indication provided that a train occupies said insulated section but has not actuated said track instrument and effective to cause said signal to display its third indication provided that a train occupies said insulated section and has actuated said track instrument.

CHARLES W. BELL. 

